John state



(No Model.)

J. STAT-E. Lifting-Jack,

No. 228,285 Patented June 1 1880.

UMTED STATES Parana Erica.

JOHN STATE, OF SPRINGFIELD, OHIO, ASSIGNOR TO FERDINAND STATE, OF SAMEPLACE.

LIFTIING-JACK.

SPECIFICATION forming part of Letters Patent No. 228,285, dated June 1,1880.

Application filed March 5, 1880.

To all whom it may concern.-

Be it known that I, JoHN STATE, of the city of Springfield, in thecounty of Clarke and State of Ohio, have invented a new and usefulImprovement in Lifting-Jacks, of which the following is a specification.

My invention relates to improvements in lifting-jacks in which two pairsof toggle-levers operate in conjunction with the screw.

The object of my invention is, primarily, to

. lift the heaviest weight with the least power second, to operate thejack with the least amount of frictional resistance; third, to retainthe load lifted at any height without endangering in the least thestrength or safety of the lifting mechanism. I attain these objects bythe mechanism illustrated in'the accompanying drawings, in Which Figure1 is a perspective view of my improved lifting-jack with one of thecap-plates over the working parts, on one side, removed. Fig. 2 is avertical longitudinal section through the center of the machine,including the socket end of its hand-lever.

Similar letters of reference indicate similar parts in the views.

A is the screw; to, a heavy fluted top nut, which, when the weight islifted, is screwed down upon the cap I), the latter resting upon the topof the body B. 0 is the lower nut under cap I). c and c aretoggle-levers formed with circular ends. Their central ends operate ingrooves cut in the inside ends of the links or levers e, of which thereare two, one on each side, and connected at their outer ends by a bolt,upon which the socket end of the hand-lever f is pivoted, between them.The point end of this lever is eccentric to its pivot or fulcrum, itsperiphery being extended farthest from the same towardthe end of thethrow of the lever as the toggles are drawn to their vertical position.For this purpose its under surface is rounded toward the point. Thisform also lessens the friction of the contacting surfaces of the leverand the body of the jack.

The top ends of the toggle-levers e" operate in a groove or semicircularslot cut in the lower ends of the sliding blocks g, which are fitted toslide up and down vertically as the (No model.)

toggle-levers are operated. The lower ends of these toggle-leversoperate in a semicircular notch in the inside ends of the links orpulllevers 6, while the lower toggle-lever, 6, has its top end operatingin a semicircular notch, also in the inside end of the links 6, and itslower ends in a similar notch out in the body of the jack at the lowerpart of the opening seen in Fig. 1, giving a solid fulcrum-point ofresistance. The slide-blocks 9 move in ways, also out in the body B atthe upper part of the opening.

The screw A is non-rotatin g, being elevated wholly by the system oflevers shown.

f has a socket for the insertion of the handlever, as seen in Fig. 2,which also shows the position of the pivot-bolt extending through it.

To operate the jack, leverf is thrown up, as shown in Fig. 1, and at thesame time it is pushed against the body, forcing the inside ends oftoggle-levers e e, by links 6, back to an angle, as seen in the figure.This movement allows blocks g to fall by their own gravity. Nut 0 is nowturned down until it touches blocks 9, leaving a space between it andcap 1) equal to the height of the lift. Power being applied to lever fas it is forced down, the toggle-levers straighten to a vertical line,the screw A, with it top nut, a, and lifting-nut 0, being lifted, asseen in Fig. 2, to a distance equal to the throw of the toggle'levers.After this movement the top or holding nut a is turned down on the screwtill it rests upon the cap I), and the same operation repeated asbefore.

The operative parts are all removable cilitate cleaning or repairs.

I claim as my improvement- 1. In a lifting-jack, the following elementsviz: a non-rotating screw, a top or holding nut, a removable cap onwhich said nut rests in sustaining the weight lifted, a lower or liftingnut under said cap, following blocks or lifters under the lifting-nut, aseries of toggleand-link or pull levers pivoted and connected therewith,as shown, and an eccentric or camheaded lever pivoted between the outerends of said links or pull-levers, for operating said to faliftingmechanism, as hereinbefore specified.

2. In a lifting-jack, the combination, with a non-rotating screw havinga top or holding nut, a lower or lifting nut, and a removable cap forsustaining the Weight lifted interposed between the latter, oflifting-blocks which may be moved freely in a vertical direction undersaid lifting-nut, operated by two pairs of toggle-levers connected bylinks with a cam ended hand-lever, as hereinbefore set forth.

3. In a liftingjaek, the combination, with the body B and non-rotatingscrew A, having nuts a and 0 and the interposed removable cap 1;, of aseries of lifting-blocks, g, togglelevers e and 0, links 6, and thecam-ended socket-piece f, pivoted between the outer ends of the latterwhereb 1 as the mechanism is 1 cap I), in combination withlifting-blocks hav- 2o ing vertical movements when opera-ted by theseries of levers specified, for the purpose set forth.

J OHN STATE.

Attest B. O. CONVERSE, B. A. ORMSBEE.

